In a construction machine such as a hydraulic excavator, various devices and pipes are disposed on a revolving fiame of a rotatable superstructure, such as hydraulic actuators for actuating a front attachment and a lower carriage, a hydraulic pump for supplying a hydraulic oil to each of the actuators, and an engine unit for actuating the hydraulic pump. These devices and associated pipes are protected by a bonnet.
A guard cover capable of being opened vertically through a hinge is mounted at a front part of the revolving frame which is positioned sideways of a boom support portion of the front attachment and on the side opposite to a cabin.
Inside the guard cover are disposed such devices as control valve for controlling the flow rate and direction of hydraulic oil to be fed to each hydraulic actuator, operation pattern change-over valve for changing over from one correlation to another between the operating direction of an operating lever and a hydraulic actuator operated thereby, filter, hydraulic oil tank, fuel tank, and battery.
These devices are usually gathered in one place for ease of work at the time of start-up of the machine or for convenience to servicing, including repair and maintenance. For example, inspection works such as inspection of the amount of oil in the fuel tank, inspection of the amount of hydraulic oil, and inspection of the battery, as well as the operation of the operation pattern change-over valve, are performed mainly by the operator of the hydraulic excavator.
On the other hand, servicing works such as checking oil leakage of the control valve, hydraulic oil tank and hose, and additional clamping of a pipe portion mounted to the control valve, are performed mainly by a serviceman sent from a manufacturing company of the hydraulic excavator. Thus, the works carried out with the guard cover open are classified into the inspection works performed by the operator of the hydraulic excavator and the servicing works performed by a serviceman.
However, according to the structure of a conventional guard cover, the operator or serviceman is required to peiform inspection or servicing of various devices while looking into the interior from an opening which is formed by opening the guard cover upward. This raises the problem that the working efficiency is low.
In the case of a guard cover as a constituent of an outer shell of a rotatable superstructure, which guard cover is formed integrally in an inverted U shape in section from an upper surface toward both side faces of the outer shell, the whole of the guard cover, which is bulky, must be opened even when inspection alone is to be conducted. Besides, in such a bulky guard cover, a support fiame for supporting the guard cover must be extended from the revolving frame of the rotatable superstructure and it has so far been an obstacle to the inspection or servicing work.